Media handing devices that process multiple document bunches must separate the documents for individual processing downstream within the media handling devices. A media separator is a component of the media handling devices. Typically, the media separator uses an ultrasonic sensor for detecting any overlapping documents.
The ultrasonic sensor reports when a detection is made as to whether the ultrasonic sensor detects: i) a clear condition, ii) a single condition, or iii) a double condition. A clear condition indicates that no document is detected by the ultrasonic sensor. A single condition indicates that one document is detected by the ultrasonic sensor. A double condition indicates one or multiple documents are detected by the ultrasonic sensor. Additionally, in situations where overlapping documents cover half of the ultrasonic sensor while the other half of the ultrasonic sensor is clear, the ultrasonic sensor will report a single condition.
A double feed recovery is performed by the media separator to separate any detected overlapping documents within the media separator. However, performance of the double feed recovery reduces throughput of document processing within the media handling device.
For purposes of maintaining adequate document processing throughput within the media handling device, the double feed recovery processing is not instantly performed when the ultrasonic sensor reports a double condition; this allows for a certain amount of time to give the documents a chance to properly separate within the media separator. However, if the double condition remains after the elapsed period of time, the double feed recover is performed. But, if the ultrasonic sensors report a single or clear condition before the elapsed period of time, the documents are assumed to have properly separated from one another and double feed recovery is not performed and document throughput within the media handling device is maintained.
One significant issue with double feed recovery is that folded documents can fool the double feed recovery processing, such that a document may appear as being successfully separated but in reality a fold in the document has passed the ultrasonic sensor. The folded documents can jam downstream processing within the media handling device and result in manual service calls to remedy the jam, and during such time until the jam is resolved the media handling device is out of service.